@doomshmuck both good ideas. I'm worried either would take away from the game as we imagined it. Nevermind that literally everything we did is first-draft and this was just the first thing we thought of, but that would be something to iterate on.
I do get the frustration of playing a difficult game without checkpoints. For a maze, I would think you still gain knowledge of where not to go, so not all progress needs to be repeated or is lost. Can you add checkpoints to a maze without taking away any of its essential maze-ness? Do you add checkpoints in wrong directions?
Maybe the easiest fix would be to just not reset enemies, so you don't have to kill the same ones over and over. Oh well. It's something to think about, and a great reason to have other people playtest.
Thanks for your feedback! It was really helpful to me.